1. Field of the Invention
The present invention is related generally to a gas laser and, more particularly, to a gas laser having a housing tube and a capillary projecting into and beyond the housing tube.
2. Description of the Related Art
A gas laser is disclosed in U.S. Pat. No. 4,649,546 corresponding to German published application No. 33 05 462. Gas lasers, such as those described therein, are usually adjusted relative to an optical bench wherein the optical bench carries the two laser mirrors which provide the resonator for the laser. The optical bench is essentially composed of metal rods which have a coefficient of thermal expansion of approximately zero, at least in the range of the operating temperature of the laser.
The known gas lasers are terminated gas tight at both ends of the housing by Brewster windows, forming a structural unit which is fixed in position at an arbitrary location of their longitudinal extent relative to the optical bench. Length changes as a consequence of temperature fluctuations have no influence on the mutual position of the laser mirrors.